1. Field of the Invention
The present invention relates to a tubular endoprosthesis which is to be implanted in an aneurysm of a patient. The invention relates also to a method for producing a tubular endoprosthesis.
2. Description of the Related Art
A weakness in a wall of an artery of a human being can lead to the local dilatation of the artery and form an aneurysm. The aneurysm can endanger the patient's life because of the risk of internal bleeding (hemorrhage) resulting from a rupture of the arterial wall. Such a rupture is the result, for example, of the application of a blood pressure to the weakened wall of the artery.
Aneurysms are conventionally treated before a rupture occurs. Two surgical operations can be carried out:
1. A conventional operation or ablation of the aneurysm is carried out.
2. A mini-invasive endovascular operation via the femoral arteries is carried out. This operation consists in excluding the aneurysm from blood circulation by positioning an endoprosthesis in the region of the aneurysm. The endoprosthesis is intended to replace the artery in the region of the aneurysm.
Although the procedure of fitting the endoprosthesis is now well known, there is still a risk that leaks will occur, that is to say that the aneurysm will not be perfectly excluded, either immediately after the operation or several months later. Such leaks are called “type I or type II endoleaks” according to their origin (migration of the endoprosthesis due to inadequate anchoring, existence of blood circulation in the excluded aneurysmal sac due to subrenal collateral criteria, etc.).
Accordingly, it is essential to monitor the endoprosthesis and the aneurysm in order to detect endoleaks and, especially, prevent a risk of post-operative rupture. It would be advisable in this case to carry out the most appropriate operation.
Such monitoring can be carried out by medical imaging, such as magnetic resonance imaging, but this is restricting for the patient.
Another possibility, described in U.S. Pat. No. 6,159,156, is to place in the aneurysm an identical pressure probe from which measurements will be collected by means of a device outside the patient's body. This document also describes the fixing of a probe to the endoprosthesis so that the probe retains a fixed position in the aneurysm.
This document proposes determining a risk of rupture when an excessively high pressure or a pressure that has changed greatly relative to a preceding measurement is detected somewhere in the aneurysm.
Nevertheless, it has been found that this solution often leads to incorrect conclusions, especially false alarms. The method therefore lacks accuracy.